Question

two angles of a triangle are 125^o and 40^o. Find the measure of the third angle

Answer 1

$$\begin{gathered} \mathrm{Let}\mathrm{ABC}\mathrm{be}\mathrm{the}∆. \\ \mathrm{Let}\angle \mathrm{A}=125°;\angle \mathrm{B}=40°;\angle \mathrm{C}=? \\ \mathrm{now},\angle \mathrm{A}+\angle \mathrm{B}+\angle \mathrm{C}=180°\left[\mathrm{Angle}\mathrm{sum}\mathrm{property}\right] \\ \Rightarrow 125°+40°+\angle \mathrm{C}=180° \\ \Rightarrow \angle \mathrm{C}=15° \end{gathered}$$